PTO pump filter recommendations/pseudo-poll

[electrycmonk]

I've reading up on PTO pump filter setups and I guess I want to ask what micron level you personally use on your PTO pumps?

I know how subjective this is and how anecdotes are very valid. I prefer them as it draws a better picture for me on what your environment is and why you chose a fine middle or coarse filter for your hydraulic system with the PTO pump.


The backhoe I got recently has a PTO pump and no filter at all. I've been looking at the different filter heads and sizes of filter.... Sheeesh, they are all over the map!

I have been using a bypass oil filter setup on my f350's for over 15 years now.... The 1 micron stuff. I know the micron level of the normal engine oil filters so, know that hydraulic filters are from ~10-50+ microns begs the metaphorical question: chocolate, strawberry, or vanilla --- or Neopolitan (rolls eyes at self).

 

[oldnslo]

Some variables to consider when looking at filters
1) Filter location: inlet or suction vs return or pressure line.
2) type of components in a system. Manual valve and gear pump or piston pump with servo or proportional control valves.
3) system pressure higher pressure usually require finer filtration.
4) nominal or absolute filter rating. Absolute filter removes 95 percent or more of the rated particles size on single pass. Nominal are more of a reference number.

For a PTO pump on a back hoe I would look at 10 micron return line filter with flow rating at least two times greater than pump flow. This allows for higher flows returning from the cylinders

 

[IceStationZebra]

Oldnslo makes valid points and for this audience I would also add hrs/yr. For example if a machine runs <100hrs a year you probably won't pay back the cost to install the filter because water will be the larger concern.

If you are running a PTO pump I'm going to assume it is a gear pump and feeds plain spool valves. Oldnslo is right on the standard recommendation of 10-12 micron to maximize component life. An alternative to sizing it twice the pump flow would be using a filter with a built-in bypass. The bypass will accommodate the short duration pressure spikes, especially useful for those of us that live in frozen tundra. If the filter doesn't have a bypass you should do a quick backpressure check at max flow with cold oil and verify the filter is rated for the pressure you see. And like Oldnslo says the worst case is often when retracting as many cylinders as possible at the same time.

If you have components with tight tolerances such as piston pump, load sense, counterbalance valves, proportional valves, etc. industry recommendations would be 3-5 micron.

The other item you need to consider is the breather. The reservoir pulls in contaminated air every time you extend a cylinder. The micron rating should equal or better than your filter. If you are making a big step down in pore size you may have to go bigger to get sufficient air flow and dirt holding capacity.

The last item I'll mention is that new oil is contaminated - especially 5 gallon pails, drums and totes. I've heard of oil samples as bad as 23/21/18 and I've personally seen 3-4" piles of metalic and non-metalic debris in drums and totes! :shocked: If you take oil cleanliness seriously you need to filler the oil before you put it in the machine. CAT and Deere agree and have been pushing their dealers to install filtration on all their bulk tanks.

ISZ

 

[electrycmonk]

(gentlemanly bow) thanks for the clarification and, for the homework guys.

I found the company website, found the users manual and parts manual(all in one) and it shows a "inline strainer" that supposed to fit in a section of pipe on the return side. No I didnt commit to memory the micron data yet but, i have it printed out and ready for a 3 ring binder so.... it will get highlighted, etc....